The present invention relates generally to harvesting machines and more particularly to a control device for controlling a transfer device on a harvesting machine, wherein the transfer device is arranged so as to be pivotable about a vertical axis and, to alter a height setting, about a horizontal axis.
Self-propelled harvesting machines, for example forage harvesters, combine harvesters, sugar cane harvesting machines and the like, usually have a transfer device, e.g. an upper discharge chute, a grain tank unloading tube, a conveyor chain or a conveyor belt, with which the crop is transferred from the harvesting machine to a transport vehicle. When the harvested crop is to be transferred continuously during a harvesting journey, for example in the case of a forage harvester, the transport vehicle must be driven parallel beside or behind the harvesting machine during the harvesting. For this purpose, the transfer device can be positioned by pivoting about the vertical axis and the horizontal axis in such a way that the discharged or exiting crop stream is deposited in the transport vehicle at the desired location.
By pivoting about the horizontal axis, the height setting of the transfer device is adapted to the height of the transport vehicles and the rising level of crops in the transport vehicle. By pivoting about the vertical axis, the transfer device is brought out of a transport position to a harvesting position. The transport position is provided for road travel, in which the transfer device, directed rearwards, is laid on a transport frame. In the case of harvesting, the transfer device often has to be swung to the right or left when harvesting a section of a field, as the transport vehicle must always travel on the already harvested area of the field section and is therefore located alternately to the right and left beside the harvesting machine. Pivoting of the transfer device about the vertical axis of rotation is furthermore used for uniform filling of the transport vehicle. If the transport vehicle is sufficiently filled at one location, the driver of the harvesting machine can swing the transfer device in such a way that the crop stream impinges on another location within the transport vehicle.
Pivoting about the vertical axis takes place generally by means of a planetary gear by which the transfer device is coupled to the harvesting machine. Unfortunately, continuous pivoting of the transfer device is not possible in most harvesting machines because housing parts of the harvesting machine, for example the driver's cab, protrude upwards above the plane in which the planetary gear is arranged. To prevent a collision with these housing parts, harvesting machines have mechanical stops located on the planetary gear to stop the rotational movement of the transfer device about the vertical axis of rotation before the transfer device can damage the housing part concerned.
This limiting of the pivot range has a particularly adverse effect in forage harvesters in which usually an upper discharge chute is arranged as the transfer device a relatively short distance behind the driver's cab. Owing to this arrangement of the upper discharge chute close behind the driver's cab, the pivot range in such machines is generally not more than 190°. That is to say, the upper discharge chute can essentially be pivoted only within the rear region of the forage harvester. At most it can pivot 10° forward of the perpendicular lateral direction. As a result of this greatly restricted pivot range of the transfer device, monitoring of the transfer device is made difficult for the driver. For monitoring and control of the transfer device, the driver must direct his eyes on the transfer region. On the other hand he must also watch the region of crop pick-up. Therefore, the driver operates the transfer device during parallel travel preferably as close as possible to the rear wall of the cab, i.e. to the front stop. The two monitoring regions that the driver has to watch are close together as a result. Nevertheless, with the current maximum pivot range the distance between the regions is still so great that the driver must constantly turn his head or must use suitably positioned mirrors for monitoring.
The design and arrangement of the upper discharge chute on a forage harvester are predetermined by the optimization of the crop flow within the forage harvester. Hence, these items are not readily variable to extend the pivot range. Similarly, it is not desirable to alter the position of the driver's cab either. Reducing the depth of the driver's cab would impair the driver's comfort. Other drawbacks are associated with this type of alteration.